Method and apparatus for residue detection on a polished wafer

Abstract

There is provided an automatic optical inspection tool of an apparatus for residue detection on polished wafers, including an inspection tool, an illumination source, capable of instantaneous entire wafer surface illumination, colour digital camera, encompassing the entire wafers surface without eclipse, in a duple of consecutive, properly delayed imaging shots and providing appropriate image resolution for tiny residue detection, computation means, implementing image processing and manipulation algorithms to enable residue detection and characterization, logic and command operations execution and camera control, the computation means accumulating an on-line created wafer images and wafer residue defects data base, the computation means providing for inspection tool worthiness monitoring, wafer handling and transportation means. A method of automatic optical self-contained inspection for pattern wafers' polishing residue detection is also provided.

Description

CROSS REFERENCE TO RELATED APPLICATIONS[0001]This application is a National Stage of International Application No. PCT / IL2005 / 001110, filed Oct. 26, 2005, and which claims the benefit of U.S. Provisional Patent Application No. 60 / 622,443, filed Oct. 26, 2004. The disclosure of the above applications are incorporated herein by reference.FIELD OF THE INVENTION[0002]The present invention pertains in general to the semiconductor integrated circuits device manufacturing. More specifically, the present invention relates to wafers processing quality inspection and, in particular, to a method and apparatus for polishing residue detection and characterization, and polishing operation working order assessment.BACKGROUND OF THE INVENTION[0003]Chemical-mechanical polishing (CMP) is a well-known process in the semiconductors manufacturing industry. It removes and planarizes metal, alloy and dielectric material layers deposited on wafer's surface. CMP typically involves mechanical polishing of th...

AI Technical Summary

Benefits of technology

[0025]In accordance with the present invention there is provided an automatic optical inspection tool of an apparatus for residue detection on polished wafers, comprising an inspection tool, an illumination source, capable of instantaneous entire wafer surface illumination, colour digital camera, encompassing the entire wafers surface without eclipse, in a duple of consecutive, properly delayed imaging shots and providing appropriate image resolution for tiny residue detection, computation means, implementing image processing and manipulation algorithms to enable residue detection and characterization, logic and command operations execution, and camera control, said computation means accumulating an on-line created wafer images and wafer residue defects data base, said computation means providing for inspection tool worthiness monitoring, wafer handling and transportation means, and an operator for controlling inspection process and results supervision and on-time process flow alternation or interruption to efficiently and timely incorporate and carry out the inspection process findings and prompts.

Problems solved by technology

It often occurs, however, that not the entire metal layer is removed, due mostly to the process control impairments, such as pads fractional damage, thereby leaving a residue on the processed wafer.

The presence of a residue might impair the quality of the final product.

The yield and productivity are adversely affected if the residue presence is not detected on time.

The prior art indirect end-point polishing on-process technique implemented in numerous manufacturers' polishing tools for process control doesn't prevent processing residue events and the inspection for remains becomes a necessity.

This process is time-consuming and labor-intensive, human error prone and its off-process implementation interferes with the manufacture process flow, causing time, productivity and production floor area losses.

They have limitations in heavily patterned wafers inspection, are off-process implemented and their inspection throughput rate is low.

Alternatively, complicated and bulky multi-beam parallel illumination and imaging principle are implemented in prior art apparatuses.

Some prior art methods utilize complicate illumination and imaging beam forming schemes, including optics and planar and spherical mirrors to encompass simultaneously entire wafer surface lighting without eclipse.

The resulting apparatuses' dimensions exceed the constraints of the available space for on-process implementation.

Some prior art schemes, incorporating diffracted light analysis, are ill suited for highly reflective metal residue discrimination on patterned wafer surface.

This method objective and apparatus arrangements are the inspection of opaque, non-polished wafers, thus making them improper for residue detection, especially on patterned wafers, with inherent ample contrast variations.

This method is ill suited for patterned, transparent upper silicon layer wafers inspection aimed at tiny defects detection.

This method is not suited to detect limited area residues, caused by polishing machine pad's surface fractional defects / malfunction.

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